JPH05163569A - Surface treatment method for sputtered alumina film - Google Patents

Abstract

(57) [Abstract] [Purpose] Suppression of corrosion of sputtered alumina film due to cleaning with pure water, and practical use of cleaning with water-based cleaning agents without using CFCs or chlorine-based organic solvents that cause environmental pollution. It is to provide a surface treatment method for a sputtered alumina film. [Structure] Oxygen gas is sent from an oxygen cylinder 7 to an ozonizer 4 to be converted into ozone gas, which is then fed into a processing tank 8. It is decomposed by irradiating it with the ultraviolet lamp 1 to generate active oxygen, which is brought into contact with the sputtered alumina film of the substrate 2 to be processed placed on the stage 9 to perform surface treatment of the film. Passivates the surface of.
Reference numeral 8 is a temperature controller for controlling the temperature of the substrate 2 to be equal to or lower than a heat resistant temperature at which peeling of the alumina film does not occur. Other methods of surface treatment in the vapor phase with active oxygen include methods such as treatment in oxygen plasma and implantation of oxygen ions. It is also possible to perform solution treatment in hydrogen peroxide water heated just before decomposition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method for a sputtered alumina film (abbreviation of an alumina film formed by sputtering), and more particularly to a surface treatment method for a sputtered alumina film which enables cleaning with pure water.

[0002]

2. Description of the Related Art An alumina film is used as a protective film for various electronic parts, and sputtering is well known as a film forming method. Although there is a cleaning process in the part manufacturing process, if you try to clean the sputtered alumina film in pure water, the film is likely to be corroded by pure water, so rinsing with pure water and pulling dry from warm water are preferred for cleaning. Nevertheless, such water-based cleaning has not been carried out, and conventionally, cleaning using a chlorine-based organic solvent such as 1,1,1-trichloroethane has been mainly performed. In addition, as a thing related to this kind of technology, for example, Modern Engineering Library, "Cleaning Metals" supervised by Japan Society of Engineers, Fujio Mamiya (published by Chijin Shokan), page 57 can be mentioned.

[0003]

The organic cleaning solvent used in the above-mentioned prior art exerts a considerable cleaning power on organic foreign matters such as wax adhered at the time of processing after film formation. It has almost no effect on the above-mentioned inorganic foreign substances. In addition, basic organic solvents such as 1,1,1-trichloroethane may destroy the ozone layer surrounding the earth, and their use is now strongly regulated due to environmental problems, and it is completely prohibited as a future direction. Therefore, it is strongly desired to develop a cleaning technique that uses an alternative cleaning agent instead of CFCs or chlorine-based organic solvents.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and to replace the organic solvent, which is expected to be more effective than the organic solvent currently in the mainstream, and to eliminate the basic organic solvent. It is an object of the present invention to provide an improved surface treatment method for a sputtered alumina film, which makes it possible to perform pure water rinsing and warm water drying, which are indispensable for carrying out water-based cleaning using a cleaning agent.

[0005]

The above object of the present invention is to bring active oxygen into contact with a sputtered alumina film in a heated state,
This is achieved by a method for surface treatment of a sputtered alumina film, which comprises the step of adding oxygen to the surface layer of the alumina film to passivate the surface. More specifically, a preferable treatment method will be described. As a method of bringing active oxygen into contact with the sputtered alumina film in a heated state, the sputtered alumina film is interposed in an active oxygen gas atmosphere, and the sputtered alumina film is heated during the treatment. That is, it has a step of setting the temperature below the heat resistant temperature. It should be noted that the meaning of setting the heat-resistant temperature or lower means a temperature range for preventing the alumina film from being separated from the substrate due to a difference in thermal expansion due to heating, since the alumina film is usually formed as a protective film of a predetermined substrate. .. Therefore, in view of the heat resistance of the sputtered alumina film, it is desirable that the processing apparatus be provided with not only a heating means but also a cooling means for the temperature control.

Further, the step of forming this active oxygen gas atmosphere is to feed ozone gas and decompose it into active oxygen under irradiation of ultraviolet rays.
A step of bringing the sputtered alumina film into contact with oxygen plasma as an oxygen plasma atmosphere may be used.

Further, the above object is a method for carrying out passivation treatment of a film by bringing active oxygen into contact with a sputtered alumina film, which comprises a step of implanting oxygen ions into the film by ion implantation. This can also be achieved by a surface treatment method for a sputtered alumina film, and also by a surface treatment method for a sputtered alumina film, which comprises a step of interposing the sputtered alumina film in an aqueous hydrogen peroxide solution heated near the decomposition temperature. Is achieved.

[0008]

According to the present invention, in order to modify the surface of the sputtered alumina film, an oxygen atom excess state (particularly active oxygen is present) is used to put the object on which the sputtered alumina film is formed into Add. This is because the pure water corrosion of the sputtered alumina film is due to the fact that the sputtered alumina film after film formation has many defects due to oxygen deficiency, unlike amorphous bulk alumina, and water molecules are easily added. It is conceivable that this defect will be improved by adding oxygen. As a result, defects on the film surface are improved and passivated with respect to pure water, and rinse with pure water and pulling and drying from warm water, which are essential for water-based cleaning, can be performed, and cleaning performance can be improved, and basicity can be improved. It is possible to use an alternative cleaning agent for an organic solvent.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for treating a sputtered alumina film in the air according to the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 is a schematic view of an apparatus configuration for performing a surface treatment of a sputtered alumina film according to an embodiment of the present invention. In the following, according to the figure, the oxygen gas supplied from the oxygen cylinder 7 is converted into ozone gas by the ozonizer 4 and sent into the processing tank 8. Ultraviolet lamp (using low pressure mercury lamp) 1
By irradiating the substrate with ultraviolet rays to generate oxygen radicals, oxygen is added to the surface of the sputtered alumina film having a thickness of about 40 to 60 nm formed on the substrate (zirconia) 2 to be processed. At this time, the temperature controller (heater) 3
The temperature of the substrate 2 to be processed is controlled below the heat resistant temperature of the sputtered alumina film through the stage 9. The treatment conditions are as follows: oxygen flow rate 1 to 10 liter / min, oxygen gas pressure 0.5 to ² kg / cm ² , ozone gas concentration 0.5 to 3
Vol% and a treatment time of 1 to 20 minutes are preferable.

In this example, a zirconia substrate was used as the substrate 2 to be treated, and the treatment was carried out at an oxygen flow rate of 3 liters / minute, an oxygen gas pressure of 0.5 kg / cm ² , an ozone gas concentration of 1 vol% and a treatment time of 20 minutes. At this time, since the heat resistant temperature of the alumina film is about 150 ° C. for the substrate 2 to be processed,
The temperature was controlled to 130 ° C or lower.

In order to examine the resistance of the alumina film treated according to the above-mentioned example and the untreated comparative example to pure water corrosion, each was left in pure water at 65 ° C. for 8 hours, and the thin film X was formed.
The change in the surface layer of the film measured by line diffraction is shown in FIG. 2 (comparative example).
3 and FIG. 3 (Example). The ozone-treated alumina film is much less likely to form a corrosion product, aluminum hydroxide Al (OH) ₃ , than the untreated film. Therefore, the progress of corrosion was slow, and the pure water corrosion of the sputtered alumina film could be suppressed by this treatment.

<Embodiment 2> FIG. 4 is a schematic view of the construction of an apparatus for carrying out the surface treatment of a sputtered alumina film according to another embodiment of the present invention. In the following, description will be given with reference to the same drawing. The hydrogen peroxide aqueous solution 10 of 5 to 35% injected into the treatment layer 8 is heated to 70 to 100% by the heater 3.
The temperature is raised to 0 ° C., and oxygen is added to the alumina film on the substrate 2 to be processed. The treatment time is preferably 1 to 20 minutes.

In this example, as in Example 1, a zirconia substrate was used as the substrate 2 to be treated, and a 10% aqueous hydrogen peroxide solution was heated to 80 ° C. and treated for 5 minutes.

As a method for evaluating the film, this alumina film and the untreated film of the comparative example were left in pure water kept at 65 ° C. for 8 hours and measured by thin film X-ray diffraction.
Similar results were obtained.

Example 3 Further, instead of the method for surface treatment of a film with active oxygen by ozone decomposition shown in Example 1, the atmosphere in the treatment tank is an oxygen plasma atmosphere, and sputtered alumina is added to this oxygen plasma. Surface treatment was performed by contacting the membrane. The plasma treatment is omitted in the drawing,
This was carried out by a commercially available parallel plate type or microwave discharge type plasma processing apparatus by a magnetron system, and in any case, the same effect as in Example 1 was obtained.

<Embodiment 4> The processing method of this embodiment utilizes ion implantation (ion implantation method) used as a means for introducing impurities into a semiconductor substrate in the manufacturing process of a semiconductor device. The same substrate as in Example 1 was mounted in the treatment tank of the ion implantation apparatus, and oxygen ions were used as the ion species to introduce active oxygen into the sputtered alumina film. Also in this case, the first embodiment
Almost the same effect was obtained.

As is clear from the above results, it is possible to remarkably improve the pure water resistance of the film by subjecting the sputtered alumina film to the oxygen addition treatment in the gas phase or in the solution, and it is possible to improve the pure water resistance of the film. It has been demonstrated that cleaning the membrane is industrially feasible.

[0018]

As described above in detail, the present invention has achieved the intended purpose. That is, by passivating the surface of the sputtered alumina film, which is easily corroded by pure water, with active oxygen, rinsing with pure water, which is indispensable for water-based cleaning, and lift-drying from warm water became possible. As a result, it becomes possible to perform cleaning using a water-based detergent that easily and efficiently removes stains strongly adhered to the surface of the object to be processed in a short time. In particular, the practical application of the cleaning of solid oil and fat stains with a water-based detergent without using CFCs or chlorine-based organic solvents, which are currently regarded as a problem of environmental pollution on a global scale, has a great effect on industry. Become.

[Brief description of drawings]

FIG. 1 is a schematic view of a surface treatment apparatus which is an embodiment of the present invention and which is performed in a gas phase.

FIG. 2 is a thin film X-ray diffraction spectrum curve diagram of a sputtered alumina film which is not subjected to a surface treatment, which is a comparative example, after standing in pure water at 65 ° C. for 8 hours.

FIG. 3 is a thin film X-ray diffraction spectrum curve diagram of a sputtered alumina film surface-treated with active oxygen according to an example of the present invention after standing in pure water at 65 ° C. for 8 hours.

FIG. 4 is a schematic view of a surface treatment apparatus which is performed in a solution according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ultraviolet lamp, 2 ... Processed substrate, 3 ... Temperature controller (heater), 4 ... Ozonizer, 5 ... Flow meter, 6 ... Pressure gauge, 7 ... Oxygen cylinder, 8 ... Processing tank, 9 ... Stage, 10 ... Over Aqueous hydrogen oxide solution.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Watanabe 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefectural Institute of Technology Hitachi, Ltd.

Claims (6)

[Claims] 1. A surface treatment method for a sputtered alumina film, which comprises the step of bringing active oxygen into contact with the sputtered alumina film in a heated state and adding oxygen to the surface layer of the alumina film to passivate the surface. 2. A method for bringing active oxygen into contact with a sputtered alumina film in a heated state is such that a sputtered alumina film is interposed in an active oxygen gas atmosphere, and the heating temperature of the sputtered alumina film during processing is kept below its heat resistant temperature. The surface treatment method for a sputtered alumina film according to claim 1, which is a step of setting and performing. 3. The method for surface treatment of a sputtered alumina film according to claim 2, wherein the step of forming the active oxygen gas atmosphere is a step of feeding ozone gas and decomposing it into active oxygen under irradiation of ultraviolet rays. 4. The method for surface treatment of a sputtered alumina film according to claim 2, which is a step of bringing the sputtered alumina film into contact with oxygen plasma by using the active oxygen gas atmosphere as an oxygen plasma atmosphere. 5. A method for passivating a sputtered alumina film by contacting it with active oxygen, the sputtered alumina film comprising a step of implanting oxygen ions into the film by ion implantation. Surface treatment method. 6. A method of bringing active oxygen into contact with a sputtered alumina film in a heated state comprises a step of interposing the sputtered alumina film in an aqueous hydrogen peroxide solution heated near the decomposition temperature. A surface treatment method for the sputtered alumina film described.